Breast cancer risk factors in Queensland women attending population-based mammography screening

Objective

To investigate the prevalence of established modifiable and non-modifiable risk factors associated with breast cancer in Queensland (Australia) women.

Study design

Cross-sectional prevalence study of 9792 women (58% of women sent the questionnaire) attending BreastScreen Queensland Screening and Assessment Services between November 2008 and February 2009. Prevalence and 95% confidence intervals were calculated for each risk factor, stratified by age-group (45–49 years, 50–59 years, 60–69 years, ≥70 years).

Main outcome measures

First-degree family history (FH) of breast cancer (mother, sister, daughter), reproductive history, behavioural factors, co-morbidities, use of hormone replacement therapy (HRT) and alternatives, and socio-demographic factors.

Results

The prevalence of first-degree FH of breast cancer was 16% and a previous diagnosis of breast cancer was 3.5%; both are considered major risk factors for breast cancer. The prevalence of modifiable breast cancer risk factors of moderate risk were: current HRT use (12%), HRT use within the past 5 years (7%), overweight [body mass index 25–29] (33%) or obesity [BMI > 30] (27%), alcohol consumption [≥11 drinks/week] (10%), sedentary behaviour (70%), and low fruit (34%) and vegetable consumption (69%). These risk factors tended to be higher in younger women (45–49 years) compared to older women (>50 years).

Conclusion

Prevalence of risk factors in Queensland women were largely consistent with other Australian and international studies. Hormone therapy use is lower than previously reported estimates in Australia and internationally. The comparatively high prevalence of modifiable lifestyle factors which have been shown to be moderately associated with breast cancer are potential targets for reducing the public health burden of breast cancer.